Production of bacteriocin-like inhibitors by group A streptococci of nephritogenic M types

Abstract

Application of a bacteriocin-typing scheme that had been designed to minimize the inhibitory effects of hydrogen peroxide and acidic metabolites demonstrated a high incidence (72%) of bacteriocin-like inhibitors belonging to 5 different production (P) types in 61 strains of group A streptococci isolated in association with the development of acute glomerulonephritis. By contrast, only 4 of 16 (25%) rheumatic fever-associated strains were inhibitor positive, and 3 of these strains were P type 604, a P type not detected in any of the nephritis isolates. The P type designation was found to be identical for all inhibitor-positive strains within each particular M serotype, regardless of whether the source was a nephritis patient or an individual having an uncomplicated streptococcal infection. The incidence of inhibitor-positive strains was particularly high in strains of M types 2, 4, 12, 25, 57, and 60; it was moderately high in M types 49, 52, and 55 and absent in M1 and M3. Although the results indicate that the bacteriocin-like inhibitors detected in this study are probably unlikely to have a direct pathogenetic role in either rheumatic fever or acute glomerulonephritis, it does seem that the present P-typing scheme is a useful epidemiological tool, particularly for the presumptive identification of and differentiation among group A streptococcus strains of nephritogenic serotypes.